Search for Chlamydia pneumoniae genes and their expression in atherosclerotic plaques of carotid arteries

Samples of atherosclerotic tissue from 58 patients undergoing carotid surge ry were analysed by tissue culture and PCR for Chlamydia pneumoniae; PCR wa s performed to detect Omp1, 16S rRNA and HSP-70 genes, To understand the ac tive pathogenic role of C, pneumoniae, a reverse transcriptase-PCR (RT-PCR) assay was applied to detect the specific RNAs expressed either in the repl icative form, or in the cryptic form found in chronic infection, The C, pne umoniae omp1 gene, encoding the major outer-membrane protein (MOMP), was de tected in 13 of 58 samples, Among these, the result was confirmed in 11 sam ples after amplification of a further target, the 16S rRNA, and the presenc e of the HSP-70 gene, encoding heat-shock protein 70, was revealed in only five cases, All the samples were negative for evidence of specific RNAs by RT-PCR, The presence of genomic DNA and absence of specific RNAs in atheros clerotic tissue samples suggests a lack of an active metabolic or persisten t infective role for C, pneumoniae. Thus, traces of C, pneumoniae DNA in th ese samples could be due to a degradative pathway of the host defensive cel lular and biochemical mechanisms.